Poison control calls up after legalization of pot

Last Updated: 2015-10-16

By Kathryn Doyle

NEW YORK (Reuters Health) - Wider availability of medical marijuana in Colorado starting in 2009 coincided with an increase in calls to poison control centers and hospital discharges, a new study found.

But the small increase in hospital discharges involving marijuana and the larger increase in poison control center calls don't necessarily mean that legalizing marijuana is dangerous to public health, lead author Dr. Jonathan M. Davis of the School of Medicine at the University of Colorado, Denver, told Reuters Health.

Because more people would be using marijuana over time, "it might be intuitive that we would see outcomes like this over time," Dr. Davis said. "The difficult questions to answer are: is this a lot, and is it important? This paper can't really answer that."

Colorado went from having no known medical marijuana dispensaries in 2006 to more than 250 in 2009 and more than 900 by 2010.

Using Colorado health databases and census estimates, the researchers found that hospital discharges coded as involving marijuana "abuse" or "dependence" rose by about 1% per month from 2007 to 2013. For every 742 medical marijuana registration applications in the state, there was one hospital discharge coded as abuse of the drug.

The study did not consider total hospital discharges, so it is not clear if the relative number of marijuana-related discharges changed over time, Dr. Davis said.

"We also don't know what else people were using when they entered the hospital," he said.

From 2004 to 2009, marijuana-related calls to a poison control center in Colorado ranked behind alcohol, cocaine, and methamphetamine. After 2009 they ranked second only to alcohol, the researchers found. There were 54 marijuana-related calls in 2009 and 136 calls in 2013.

Many poison center calls were related to marijuana edibles, which are often packaged to look like cookies or candy, according to Dr. Bettina Friese of the Prevention Research Center in Oakland, California, who was not part of the new study.

"That would be either because kids got ahold of them and ate them because they thought it was candy, or people overdosed," Dr. Friese told Reuters Health.

States considering marijuana legalization should seriously consider regulating the edibles market, she said.

"We need to do a better job of regulating edibles in terms of dosage and letting people know what's in it," and with packaging that doesn't appeal to kids, she said.

Marijuana abuse treatment admissions in the Denver area rose from 2004 to 2008 and declined after 2009. Marijuana-related arrests also decreased after 2009, the authors reported in an article online September 15 in the American Journal of Preventive Medicine.

Treatment admissions likely dipped due to the decrease in arrests and mandatory drug sentencing after decriminalization, Dr. Davis said. "It's difficult to say, based on this data alone, is this really a bad thing."

About 9% of marijuana users will face dependence, and use is becoming more common, so dealing with dependence is still an issue, Dr. Friese said.

Also, as marijuana becomes more "normalized," teens tend to think it's safe, but some research indicates using the drug may have cognitive or I.Q. effects for teens, she said. The minimum age for legal medical marijuana registration is 18, and for recreational use, 21.

"I think we're all learning as we're going along, each state is trying to do something slightly different and taking other states into account," Dr. Friese said.

As far as we know now, medical marijuana access is "probably not harmless, but I don't want people to say the sky is falling in Colorado," Dr. Davis said.

The National Institute on Drug Abuse funded this research.

SOURCE: http://bit.ly/1Neso9C

Am J Prev Med 2015.